This invention relates to the field of transducers used alternately as speakers and microphones, and particularly to an improved input/output transducer with a damping arrangement to provide optimal frequency response regardless of the operational mode.
A small inexpensive speaker of the type typically used as microphones in, for example, portable two-way communications devices, usually has peaks and valleys in its frequency response. Since such a response is acceptable in a speaker but not acceptable in a microphone, it would be desirable to damp the transducer, either electrically or mechanically, to flatten this response and this has been done in the prior art. Flattening the response, however, results in lowered audio power output which is acceptable in the speaker mode. One main reason for the differing level requirements in the two modes arises from the fact that the unit is typically held near the mouth whether the user is speaking or listening. Thus the distances to mouth and ear are quite different. A need has thus existed for a simple inexpensive means of optimizing the transducer in both modes of operation.